The Effect of Dexmedetomidine on Oxidative Stress Response Following Cerebral Ischemia-Reperfusion in Rats and the Expression of Intracellular Adhesion Molecule-1 (ICAM-1) and S100B

Dexmedetomidine compared to low-dose ketamine better protected not only the brain but also the lungs in acute ischemic stroke

BACKGROUND

Dexmedetomidine (DEX) and low-dose ketamine (KET) present neuroprotective effects in acute ischemic stroke (AIS); however, to date, no studies have evaluated which has better protective effects not only on the brain but also lungs in AIS.

METHODS

AIS-induced Wistar rats (390 ± 30 g) were randomized after 24-h, receiving dexmedetomidine (STROKE-DEX, n = 10) or low-dose S(+)-ketamine (STROKE-KET, n = 10). After 1-h protective ventilation, perilesional brain tissue and lungs were removed for histologic and molecular biology analysis. STROKE animals (n = 5), receiving sodium thiopental but not ventilated, had brain and lungs removed for molecular biology analysis. Effects of DEX and KET mean plasma concentrations on alveolar macrophages, neutrophils, and lung endothelial cells, extracted primarily 24-h after AIS, were evaluated.

RESULTS

In perilesional brain tissue, apoptosis did not differ between groups. In STROKE-DEX, compared to STROKE-KET, tumor necrosis factor (TNF)-α and vascular cell adhesion molecule-1 (VCAM-1) expressions were reduced, but no changes in nuclear factor erythroid 2-related factor-2 (Nrf2) and super oxide dismutase (SOD)-1 were observed. In lungs, TNF-α and VCAM-1 were reduced, whereas Nrf2 and SOD-1 were increased in STROKE-DEX. In alveolar macrophages, TNF-α and inducible nitric oxide synthase (M1 macrophage phenotype) were lower and arginase and transforming growth factor-β (M2 macrophage phenotype) higher in STROKE-DEX. In lung neutrophils, CXC chemokine receptors (CXCR2 and CXCR4) were higher in STROKE-DEX. In lung endothelial cells, E-selectin and VCAM-1 were lower in STROKE-DEX.

CONCLUSIONS

In the current AIS model, dexmedetomidine compared to low-dose ketamine reduced inflammation and endothelial cell damage in both brain and lung, suggesting greater protection.

The Effects of Dexmedetomidine on Abdominal Aortic Occlusion-Induced Ovarian Injury via Oxidative Stress and Apoptosis

Ischemia/reperfusion (I/R) induced ovarian damage is caused by various diseases such as ovarian torsion, ovarian transplantation, cardiovascular surgery, sepsis, or intra-abdominal surgery. I/R-related oxidative damage can impair ovarian functions, from oocyte maturation to fertilization. This study investigated the effects of dexmedetomidine (DEX), which has been shown to exhibit antiapoptotic, anti-inflammatory, and antioxidant effects, on ovarian I/R injury. We designed four study groups: group 1 (n = 6): control group; group 2 (n = 6): only DEX group; group 3 (n = 6): I/R group; group 4 (n = 6): I/R + DEX group. Then, ovarian samples were taken and examined histologically and immunohistochemically, and tissue malondialdehyde (MDA) and glutathione (GSH) levels were measured. In the I/R group MDA levels, caspase-3, NF-κB/p65, 8-OHdG positivity, and follicular degeneration, edema, and inflammation were increased compared to the control group (p = 0.000). In addition, GSH levels were significantly decreased in the I/R group compared to the control group (p = 0.000). On the other hand, in the I/R + DEX treatment group MDA levels, caspase-3, NF-κB/p65, 8-OHdG positivity, follicular degeneration, edema, and inflammation findings were decreased than in the I/R group (p = 0.000, p = 0.005, p = 0.005, p = 0.001, p = 0.005, respectively). However, GSH levels increased significantly in the I/R + DEX treatment group compared to the I/R group (p = 0.000). DEX protects against ovarian I/R injury through antioxidation and by suppressing inflammation and apoptosis.

Dexmedetomidine Attenuates Hypoxia/Reoxygenation Injury of H9C2 Myocardial Cells by Upregulating miR-146a Expression via the MAPK Signal Pathway

INTRODUCTION AND OBJECTIVE

Dexmedetomidine (Dex) and a number of miRNAs contribute to ischemia/reperfusion injury. We aimed to explore the role of Dex and miR-146a on myocardial cells injured by hypoxia/reoxygenation (H/R).

METHOD

H9C2 cells were injured by H/R. Cell viability was tested using the cell counting kit-8. Lactate dehydrogenase (LDH) activity, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) levels were determined using commercial kits. Flow cytometry was performed to determine apoptosis rate and reactive oxygen species (ROS) level. Protein and mRNA levels were assessed using Western blot and qPCR.

RESULTS

miR-146a expression and cell viability of H9C2 cells were downregulated under the circumstance of H/R injury. The tendency could be reversed by Dex, which could also upregulate SOD activity and decrease apoptosis, LDH activity, MDA, 78-kDa glucose-regulated protein (GRP78), and C/EBP homologous protein (CHOP) levels of H9C2 cells. GRP78, CHOP levels, and cell viability were negatively modulated by miR-146a. Dex elevated cell viability, catalase, MnSOD, and NAD(P)H dehydrogenase (NQO1) levels but suppressed apoptosis rate, GRP78, and CHOP levels by increasing miR-146a expression and downregulating ROS, phosphorylation of p38, and extracellular signal-regulated kinases 1/2 levels. By using SB203580 (SB), the p38 mitogen-activated protein kinase (MAPK) inhibitor, Dex or the inhibition of miR-146 upregulated cell viability but downregulated GRP78 and CHOP levels.

CONCLUSION

Dex might regulate miR-146a expression, which could further modulate the endoplasmic reticulum stress and oxidative stress and eventually affect the cell viability and apoptosis of myocardial cells injured by H/R via the MAPK signal pathway.

Dexmedetomidine reduces the apoptosis of rat hippocampal neurons via mediating ERK1/2 signal pathway by targeting miR-155

Rat hippocampal neurons were isolated and divided into Normal, oxygen glucose deprivation/reoxygenation (OGD/R), OGD/R + DEX, OGD/R + NC mimic, OGD/R + miR-155 mimic and OGD/R + DEX + miR-155 mimic groups. In OGD/R group, LDH, ROS and MDA levels and apoptosis rate was increased, with up-regulations of miR-155, Cyt c and Bax/Bcl-2 ratio, but decreases of SOD, GSH-Px and MMP levels, as well as down-regulations of p-ERK1/2/ERK1/2. As compared to the OGD/R group, parameters above in the OGD/R + DEX group were ameliorated evidently, while OGD/R + miR-155 mimic group manifested the opposite changes. Besides, miR-155 mimic could abolish the protective effect of DEX on the hippocampal neurons under OGD/R. DEX, via down-regulating the expression of miR-155, could activate the ERK1/2 pathway, thereby mitigating the apoptosis and oxidative stress injury and increasing the MMP, thereby protecting hippocampal cells from OGD/R injury.

Effects of dexmedetomidine on immune function, renal function and inflammatory factors of patients undergoing percutaneous nephrolithotomy under general anesthesia

The present study was designed to determine the effects of dexmedetomidine on immune function, renal function and inflammatory factors in patients undergoing percutaneous nephrolithotomy under general anesthesia. A total of 177 patients with kidney calculi who underwent percutaneous nephrolithotomy in The Second Affiliated Hospital of Fujian Medical University were enrolled, in which 91 patients were treated with dexmedetomidine during surgery (research group) and 86 patients were not sedated during surgery (control group). The vital signs, renal function, inflammatory factors and immune function during surgery between the two groups were compared. Patients in the research group showed improved vital signs, renal function, inflammatory factors and immune function compared with the control group (P<0.05), and also experienced a significantly shorter hospitalization time (P<0.001). Therefore, the present results suggested that with a relatively high safety profile, use of dexmedetomidine for sedation can effectively protect renal and immune functions, and reduce the inflammatory response of patients during percutaneous nephrolithotomy. Thus, dexmedetomidine may have be potentially applied in clinical practice.

Protective effects of dexmedetomidine on ischaemia-reperfusion injury in an experimental rat model of priapism

The study aimed to investigate the effects of dexmedetomidine against ischaemia-reperfusion injury occurring after priapism in a model of induced-priapism in rats. A total of 18 male rats were randomised into three groups. Group 1 was the control group. A priapism model was performed rats in Group 2 and then ischaemia-reperfusion injury was evaluated. Group 3 had similar procedures to the rats in Group 2. Rats in Group 3 additionally had 100 μg/kg dexmedetomidine administered intraperitoneally immediately after reperfusion. Blood and tissue samples were analysed. Biochemical analysis of blood samples revealed a decrease in the levels of the pro-inflammatory cytokines including interleukin-1 beta (IL-1 Beta), interleukin-6 (IL-6), and tumour necrosis factor-alpha (TNF-alpha) in Group 3 compared to Group 2 (p:.04, p:.009 and p:.009, respectively). Similarly, the highest malondialdehyde (MDA) level was in Group 2 (p:.002). The levels of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities were significantly higher in Group 3 than that of Group 2 (p:.037 and p:.045, respectively). Direct microscopic examinations revealed positive changes in desquamation, oedema, inflammation and vasocongestion scores in Group 3 compared to Group 2 (p:.007, p:.008, p:.007 and p:.006, respectively). Dexmedetomidine has a protective effect against ischaemia-reperfusion injury in penile tissue.

Dexmedetomidine Resists Intestinal Ischemia-Reperfusion Injury by Inhibiting TLR4/MyD88/NF-κB Signaling

BACKGROUND

Intestinal ischemia/reperfusion (I/R) is a common clinical problem that occurs during various clinical pathological processes. Dexmedetomidine (DEX), a widely used anesthetic adjuvant agent, can induce protection against intestinal I/R in vivo; however, the underlying mechanism is not fully understood. In the present study, we aimed to investigate the protective effects of DEX and examine whether its mechanism was associated with the TLR4/MyD88/NF-κB signaling pathway.

METHODS

Sprague-Dawley rats were pretreated with DEX and then subjected to I/R-induced intestinal injury. In vivo, intestinal histopathological examination and scoring were performed, the levels of serum intestinal fatty acid-binding protein (I-FABP), intestinal tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and expression levels of TLR4, MyD88, and NF-κB in the intestine were determined. In in vitro experiments, the human colon carcinoma cell line (Caco-2) was incubated with DEX before deprivation/reoxygenation (OGD/R) treatment. The cell viability of Caco-2 cells, the levels of lactate dehydrogenase (LDH), TNF-α, and IL-1β in the supernatant, as well as protein expression of TLR4, MyD88, and NF-κB in Caco-2 cells, were measured. Statistical analysis was performed using SPSS version 21.0.

RESULTS

DEX preconditioning significantly reduced the intestinal pathological Chiu's score, serum I-FABP, intestinal TNF-α, IL-1β levels, and the protein expression of TLR4, MyD88, and NF-κB in the rats with intestinal I/R injury. Similarly, in vitro, DEX pretreatment protected against OGD/R-induced Caco-2 cell damage and inhibited TLR4/MyD88/NF-κB signaling, as evidenced by increased cell viability, decreased LDH activity, reduced TNF-α and IL-1β levels, as well as downregulated TLR4, MyD88, and NF-κB protein levels.

CONCLUSIONS

Our findings suggested that DEX could reduce intestinal I/R injury in rats and OGD/R damage in Caco-2 cells, and this protection might be attributed to antiinflammatory effects and inhibition of the TLR4/MyD88/NF-κB signaling pathway.

Peripheral Blood S100B Levels in Autism Spectrum Disorder: A Systematic Review and Meta-Analysis

The S100 calcium-binding protein beta subunit (S100B) protein, which mostly exists in the central nervous system, is commonly noted as a marker of neuronal damage. We conducted the first systematic review with meta-analysis to compare peripheral blood S100B levels in individuals with ASD with those in healthy controls. A systematic search was carried out for studies published before May 5, 2020. In total, this meta-analysis involved ten studies with 822 participants and 451 cases. The meta-analysis revealed that individuals with ASD had higher peripheral blood S100B levels than healthy controls [standardized mean difference (SMD) = 0.97, 95% confidence interval (95% CI) = 0.41–1.53; p < 0.001]. Peripheral blood S100B levels may have potential as a useful biomarker for ASD.

Dexmedetomidine Attenuates Glutamate-Induced Cytotoxicity by Inhibiting the Mitochondrial-Mediated Apoptotic Pathway

Background

Glutamate (GLU) is the most excitatory amino acid in the central nervous system and plays an important role in maintaining the normal function of the nervous system. During cerebral ischemia, massive release of GLU leads to neuronal necrosis and apoptosis. It has been reported that dexmedetomidine (DEX) possesses anti-oxidant and anti-apoptotic properties. The objective of this study was to investigate the effects of DEX on GLU-induced neurotoxicity in PC12 cells.

Material/Methods

PC12 cells were treated with 20 mM GLU to establish an ischemia-induced injury model. Cell viability was accessed by MTT assay. MDA content and SOD activity were analyzed by assay kits. Apoptosis rate, ROS production, intracellular Ca²⁺ concentration, and MMP were evaluated by flow cytometry. Western blot analysis was performed to analyze expressions of caspase-3, caspase-9, cyt-c, bax, and bcl-2.

Results

PC12 cells treated with GLU exhibited reduced cell viability and increased apoptosis rates, which were ameliorated by pretreatment with DEX. DEX significantly increased SOD activity, reduced content of MDA, and decreased production of ROS in PC12 cells. In addition, DEX clearly reduced the level of intracellular Ca²⁺ and attenuated the decline of MMP. Moreover, DEX notably reduced expressions of caspase-3, caspase-9, cyt-c, and bax and increased expression of bcl-2.

Conclusions

Our findings suggest that DEX can protect PC12 cells against GLU-induced cytotoxicity, which may be attributed to its anti-oxidative property and reduction of intracellular calcium overload, as well as its ability to inhibit the mitochondria-mediated apoptotic pathway.

Organ-Protective Effects and the Underlying Mechanism of Dexmedetomidine

Dexmedetomidine (DEX) is a highly selective α2 adrenergic receptor (α2AR) agonist currently used in clinical settings. Because DEX has dose-dependent advantages of sedation, analgesia, antianxiety, inhibition of sympathetic nervous system activity, cardiovascular stabilization, and significant reduction of postoperative delirium and agitation, but does not produce respiratory depression and agitation, it is widely used in clinical anesthesia and ICU departments. In recent years, much clinical study and basic research has confirmed that DEX has a protective effect on a variety of organs, including the nervous system, heart, lungs, kidneys, liver, and small intestine. It acts by reducing the inflammatory response in these organs, activating antiapoptotic signaling pathways which protect cells from damage. Therefore, based on wide clinical application and safety, DEX may become a promising clinical multiorgan protection drug in the future. In this article, we review the physiological effects related to organ protection in α2AR agonists along with the organ-protective effects and mechanisms of DEX to understand their combined application value.

Targeting Oxidative Stress and Inflammation to Prevent Ischemia-Reperfusion Injury

The cerebral ischemia injury can result in neuronal death and/or functional impairment, which leads to further damage and dysfunction after recovery of blood supply. Cerebral ischemia/reperfusion injury (CIRI) often causes irreversible brain damage and neuronal injury and death, which involves many complex pathological processes including oxidative stress, amino acid toxicity, the release of endogenous substances, inflammation and apoptosis. Oxidative stress and inflammation are interactive and play critical roles in ischemia/reperfusion injury in the brain. Oxidative stress is important in the pathological process of ischemic stroke and is critical for the cascade development of ischemic injury. Oxidative stress is caused by reactive oxygen species (ROS) during cerebral ischemia and is more likely to lead to cell death and ultimately brain death after reperfusion. During reperfusion especially, superoxide anion free radicals, hydroxyl free radicals, and nitric oxide (NO) are produced, which can cause lipid peroxidation, inflammation and cell apoptosis. Inflammation alters the balance between pro-inflammatory and anti-inflammatory factors in cerebral ischemic injury. Inflammatory factors can therefore stimulate or exacerbate inflammation and aggravate ischemic injury. Neuroprotective therapies for various stages of the cerebral ischemia cascade response have received widespread attention. At present, neuroprotective drugs mainly include free radical scavengers, anti-inflammatory agents, and anti-apoptotic agents. However, the molecular mechanisms of the interaction between oxidative stress and inflammation, and their interplay with different types of programmed cell death in ischemia/reperfusion injury are unclear. The development of a suitable method for combination therapy has become a hot topic.

Preclinical Evidence and Mechanism of Xingnaojing Injection for Cerebral Ischemia: A Systematic Review and Meta-Analysis of Animal Studies

Objectives

Cerebral ischemia can cause severe harm to people's health with the characteristics of high incidence, high disability, and high mortality. Xingnaojing injection (XNJI) is widely used in the treatment of cerebral ischemia. The aim of this review is to evaluate the efficacy and mechanism of XNJI in animal models of cerebral ischemia.

Methods

Total seven electronic databases in English or Chinese (CNKI, Wanfang, VMIS, PubMed, MEDLINE, Embase, and the Cochrane Library) about most experiments and studies which came out before June 2018 of XNJI for cerebral ischemia have been searched. Data extraction, quality assessment, and meta-analysis are conducted according to the Cochrane standards and RevMan 5.3 software.

Results

We have identified 23 eligible studies and made a meta-analysis based on these studies. Meta-analysis shows that XNJI contributes significantly to reduction in neurological deficit score (P = 0.0002, MD = −1.25, 95% CI: −1.92, −0.58) compared with the control group of cerebral ischemia. Subgroup analytic results demonstrate that XNJI has been more effective in animal model of cerebral ischemia-reperfusion injury (P = 0.009, MD = −1.35, 95%CI: −2.36, −0.34) than that of permanent cerebral ischemia (P = 0.0002, MD = −1.08, 95%CI: −1.66, −0.51). Compared with control group, XNJI could remarkably reduce cerebral infarction area (P < 0.00001, MD = −14.98, 95%CI: −21.36, −8.59), brain edema (P < 0.00001, MD = −4.64, 95%CI: −5.38, −3.90), and neuronal cell apoptosis (P < 0.0001, MD = −12.21, 95%CI: 18.05, −6.37). Meanwhile, the meta-analysis shows that XNJI has a significant anti-inflammatory effect, and the levels of TNF-α, IL-6, and IL-1β are significantly reduced by XNJI (P = 0.001, MD = −4.13, 95%CI:−6.68, −1.58; P < 0.00001, MD = −119.23, 95%CI: −138.04, −100.43; P = 0.21, MD = −228.69, 95% CI: −586.20, 128.83). Additionally, XNJI could raise the body's antioxidant function and the level of SOD and GSH-Px (P = 0.002, MD = 53.02, 95% CI: −20.52, 85.78; P = 0.01, MD = 8.65, 95% CI: 1.77, 15.48) and decrease the level of MDA (P < 0.00001, MD = −4.16, 95% CI: −5.50, −2.82).

Conclusion

XNJI might be effective in cerebral ischemia by regulating oxidative stress and inflammatory reaction.

Taurine enhances the protective effect of Dexmedetomidine on sepsis-induced acute lung injury via balancing the immunological system

Sepsis, an overwhelming systemic inflammatory disease, is the leading cause of acute lung injury (ALI). Despite plenty of researches have been done, effective drugs treating septic ALI are still eagerly needed in the clinic. Dexmedetomidine (Dex), a potent alpha-2 adrenoreceptor agonist, has been reported to possess antioxidant, anti-apoptosis and anti-inflammatory abilities. Taurine, a kind of intracellular free amino acid, has been used to treat various diseases. This study aimed to explore the combination effect of Dex and Taurine on septic ALI and the underlying mechanism in vivo. The establishment of septic ALI was set up in SD rats by cecal ligation and puncture (CLP) operation. Results indicated that Dex or Taurine could reduce septic ALI-induced cell apoptosis via decreasing caspase-3 activity. However, the combination of Dex or Taurine produced greater effect. Besides that, Dex combined with Taurine could better promote cell proliferation with remarkably elevated Ki67 expression. The combination of Dex and Taurine significantly suppressed the activation of NF-κB pathway via inhibiting P65 phosphorylation and P65 nuclear translocation, leading to the down-regulation of interleukin (IL)-6 and IL-1β. Moreover, co-administration of Dex and Taurine alleviated the imbalance of Th1/Th2 induced by septic ALI to a great extent. All in all, our study suggested the synergistic therapeutic effect of Dex and Taurine on septic ALI.

Improvement of postoperative cognitive dysfunction and attention network function of patients with ischemic cerebrovascular disease via dexmedetomidine

The protective effect of dexmedetomidine on cognitive dysfunction and decreased attention network function of patients with ischemic cerebrovascular disease after stenting was investigated. Fifty-eight patients with ischemic cerebrovascular disease undergoing stenting in Guizhou Provincial People's Hospital were selected and randomly divided into control group (n=29) and dexmedetomidine group (n=29). The dexmedetomidine group was treated with dexmedetomidine before induced anesthesia, while the control group was given the same dose of normal saline; and the normal volunteers of the same age were selected as the normal group (n=29). At 3 days after operation, the levels of serum S100B and nerve growth factor (NGF) in each group were detected using the enzyme-linked immunosorbent assay, and the level of brain-derived neurotrophic factor (BDNF) was detected via western blotting. Montreal cognitive assessment (MoCA) and attention network test (ANT) were performed. Moreover, the cognitive function and attention network function, and the effects of dexmedetomidine on cognitive function and attention network function were evaluated. The concentrations of serum S100B and NGF in dexmedetomidine group was lower than those in control group (P<0.01). The results of western blotting showed that the levels of serum BDNF in control group and dexmedetomidine group were significantly lower than that in normal group (P<0.01), and it was higher in dexmedetomidine group than that in control group (P<0.01). Besides, both MoCA and ANT results revealed that the visual space and executive function scores, attention scores, delayed memory scores, targeted network efficiency and executive control network efficiency in dexmedetomidine group were obviously higher than those in control group (P<0.01). The cognitive function and attention network function of patients with ischemic cerebrovascular disease have a certain degree of damage, and the preoperative administration of dexmedetomidine can effectively improve the patient's cognitive dysfunction and attention network function after operation.

A Review of Anesthetic Effects on Renal Function: Potential Organ Protection

BACKGROUND

Renal protection is a critical concept for anesthesiologists, nephrologists, and urologists, since anesthesia and renal function are highly interconnected and can potentially interfere with one another. Therefore, a comprehensive understanding of anesthetic drugs and their effects on renal function remains fundamental to the success of renal surgeries, especially transplant procedures. Some experimental studies have shown that some anesthetics provide protection against renal ischemia/reperfusion (IR) injury, but there is limited clinical evidence.

SUMMARY

The effects of anesthetic drugs on renal failure are particularly important in the context of kidney transplantation, since the conditions of preservation following removal profoundly influence the recovery of organ function. Currently, preservation procedures are typically based on the usage of a cold-storage solution. Some anesthetic drugs induce anti-inflammatory, anti-necrotic, and anti-apoptotic effects. A more thorough understanding of anesthetic effects on renal function can present a novel approach for developing organ-protective strategies. The aim of this review is to discuss the effects of different anesthetic drugs on renal function, with particular focus on IR injury. Many studies have demonstrated the organ-protective effects of some anesthetic drugs, specifically propofol, which indicate the potential of some anesthetics to introduce novel organ protective targets. This is not surprising, since lipid emulsions are major components of propofol, which accumulating data show provide organ protective effects against IR injury. Key Messages: Thorough understanding of the interaction between anesthetic drugs and renal function remains fundamental to the delivery of safe perioperative care and to optimizing outcomes after renal surgeries, particularly transplant procedures. Anesthetics can be repurposed for organ protection with more information about their effects, especially during transplant procedures. Here, we review the effects of different anesthetic drugs - specifically those that contain lipids in their structure, with special reference to IR injury.

Apurinic/apyrimidinic endonuclease 1 (APE1) contributes to resveratrol‑induced neuroprotection against oxygen‑glucose deprivation and re‑oxygenation injury in HT22 cells: Involvement in reducing oxidative DNA damage

Resveratrol, a naturally occurring polyphenolic compound, exhibits a neuroprotective role in models of central nervous system diseases, including cerebral ischemia/reperfusion injury. Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunctional enzyme that contributes to base excision repair of oxidative DNA damage and redox activation of transcription factors, associated with neuronal survival against hypoxic‑ischemic injury. It was hypothesized that resveratrol protects HT22 cells against oxygen‑glucose deprivation and re‑oxygenation (OGD/R)‑induced injuries through upregulation of APE1. It was demonstrated that resveratrol pretreatment significantly increased the viability of HT22 cells and decreased the release of lactate dehydrogenase (LDH), accompanied by the upregulation of APE1 mRNA, and protein levels, as well as the activity of APE1 under OGD/R conditions. In addition, resveratrol reversed OGD/R‑induced oxidative DNA damage as evidenced by the decreases in the levels of 8‑hydroxy‑2'‑deoxyguanosine and APE sites. However, APE1 knockdown using short hairpin RNA sequence targeting APE1 abolished resveratrol‑elicited beneficent effects against OGD/R‑induced cytotoxicity and oxidative stress. This was indicated by decreased cell viability, superoxide dismutase activity and glutathione levels, and increased LDH release and reactive oxygen species levels. The results of the present study indicate that APE1 contributes to the protective effects of resveratrol against neonatal hypoxic‑ischemic brain injuries, and suggest that DNA repair enzymes, including APE1, may be a unique strategy for neuroprotection against this disease.

The protective effects of ischemic preconditioning on rats with renal ischemia-reperfusion injury and the effects on the expression of Bcl-2 and Bax

The aim of the present study was to investigate the protective effects of ischemic preconditioning on rats with renal ischemia-reperfusion injury and the effects on the expression of Bcl-2 and Bax. Thirty-six SD rats were randomly divided into three groups (n=12) including sham operation (S) group, ischemia-reperfusion group (I/R) group and ischemic preconditioning (IP) group. After anesthesia with intraperitoneal injection of chloral hydrate, bilateral renal pedicles were clipped for 45 min, followed by perfusion for 6 h to establish the I/R model. Both kidneys in rats of S group were separated and exposed for 45 min, but renal pedicles were not clipped. In IP group, bilateral renal pedicles were clipped for 5 min, followed by perfusion for 5 min, this procedure was repeated 3 times. Then bilateral renal pedicles were clipped for 45 min, followed by perfusion for 6 h. Blood samples were collected and rats were sacrificed to collect renal tissue. Levels of serum creatinine (Cr) and blood urea nitrogen (BUN) were measured. Activity of superoxide dismutase (SOD) was measured by xanthine oxidase assay. Degree of renal injury was evaluated by H&E staining. TUNEL kit was used to detect the number of apoptotic cells in renal tissue. Expression levels of Bcl-2 and Bax were detected by semi-quantitative PCR and western blot analysis at mRNA and protein levels, respectively. Results showed that levels of Cr and BUN in I/R and IP groups were significantly higher than those in S group, and levels of Cr and BUN in I/R group were significantly higher than that in IP group (P<0.05). Activity of SOD in I/R group and IP group were significantly lower than those in S group, and activity of SOD in I/R group were significantly lower than those in IP group (P<0.05). H&E staining showed that, compared with S group, renal injury in the I/R and IP groups was more serious than that in the S group, and I/R group was more serious than the IP group (P<0.05). TUNEL apoptosis assay showed that number of apoptotic cells in IP and I/R groups were significantly higher than that in the S group (P<0.01). Semi-quantitative PCR and western blot analysis showed that, compared with the S group, expression levels of Bcl-2 mRNA and protein were significantly decreased, expression levels of Bax mRNA and protein were significantly increased, and the ratio of Bcl-2/Bax was significantly decreased in the IP and I/R groups (P<0.01). Compared with the I/R group, expression level of Bcl-2 was significantly increased, the level of Bax was significantly deceased, and the ratio of Bcl-2/Bax was significantly increased in the IP group (P<0.01). As a result, ischemic preconditioning can protect rats with renal ischemia-reperfusion injury possibly by increasing the expression level of Bcl-2 and decreasing the expression level of Bax.